On the enhancement of natural convection heat transfer with multi-branching fins

It is numerically investigated if a multi-branching fin would dissipate more heat than a fin having only two branches under laminar natural convection conditions. The study involves varying the number of branches and offset among them, symmetric and asymmetric arrangement of branches and orientation of the fins to the direction of gravity etc. It is found that multi-branching fins perform slightly better (4% higher) than fins having only two branches when gravity acts along the length of the fins. In this orientation highest heat dissipation is achieved for a fin configuration having four branches (n = 4) arranged such that α1 = 100°, β = 66.66° (α1 being the inclination of the first branch and β being the offset among the branches). Though multi-branching fins exhibit poor heat dissipation in two other orientations, the possible next best configurations are envisioned. More importantly, when the direction of gravity acts along the thickness of the fin-stem, asymmetric arrangement of branches (n = 2, α1 = 90°, β = 60°) results in 14.7% enhancement in heat dissipation relative to optimal symmetric arrangement (n = 2, α1 = 70°, β = 140°). It is observed that the average temperature of fins is higher in asymmetric arrangements. The buoyant fluid flow and heat transfer characteristics are explained. The maximum heat dissipated by the fins are 0.69579 W, 0.848 W and 0.837 W in vBhF, vBvF and hBvF orientations respectively.